Monday, December 25, 2006

Cicada Ecdysis

Cicadas (Order Hemiptera- True Bugs) are devided into two families, Tettigarctidae (the members of which are largely extinct) and Cicadidae (to which these specimens belong). Here it is shown emerging from its penultimate instar (life stage). The term used for shedding the previous cuticle is ecdysis. Beside this pictures is a second specimen showing a cast-off cuticle.

Many cicadas undergo life-cycles lasting 3-5 years (though some as long as 17), the immature stages of which are spent underground. Notice how the forelegs are enlarged and adapted for digging, which is characteristic of ground-dwelling insects.

Cicadas are known for the singing, which is amongst the loudest produced by any insect. Interestingly, only the males sing, and do this by means of an organ called a tymbal. Most other 'singing' insects (especially Orthoptera- the grasshoppers, cricketcs, etc) do so by means of scraping one body part against another.